Western electric 272 a brochure

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BELL SYSTEM PRACTICES SECTION AB46.272A
IRANSMISSION ENGINEERING AND DATA ISSUE I, OCTOBER I950
ELECTRON TUBE DAYA ALETi CO. STANDARD

TRIODE .
LOW POWER AMPLIFIER /9513! 51861716

DESCRIPTION

The 272A is a triode having an indirectly heated cathode. It is designed for use as a
radio-frequency antenna-coupling amplifier, low-power audio-frequency amplifier,
detector or modulator.

CHARACTERISTICS

Heater Voltage 10.0 volts
Maximum Plate Voltage 180 volts
Amplification Factor . 6.0

ELECTRON TUBE DATA SHEET

FILE: GENERAL PURPOSE SECTION
3' 272A

TRIODE

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272A - PAGE 2

GENERAL CHARACTERISTICS

ELECTRICAL DATA

Heater Voltage, A-C or D-C 10.0 volts
Heater Current , 320 milliamperes
Direct Interelectrode Capacitances (without external shield)

Grid to Plate 2.8 uuf

Input , , . , , . . , . . . . . . . , 3.1 uuf

Output , . , . . , . . , . . . 2.5 uuf

MECHANICAL DATA

Cathode . . . , . . . Coated unipotential

Bulb . . , . . . ST14

Base , , . , , . . . Medium 5-pin, with bayonet pin
Mounting Position . Any

Dimensions and pin connections shown in outline drawing on Page 5

MAXIMUM RATINGS, Design-Cenier Values

Plate Voltage . . . . . 180 volts
Plate D'Bsipation , 2.0 watts
Plate Current . 12.0 milliamperes
Heater-Cathode Voltage I 100 volts

TYPICAL OPERATING CONDITIONS AND CHARACTERISTICS - CLASS A1 AMPLIFIER

Plate Voltage , 100 120 160 180 volts

Grid Voltage -7 -10 -17 -21 volts

Peak A-F Grid Voltage 7 10 17 21 volts

Plate Current . . . 6.6 6.7 6.6 6.2 milliamperes
Transconductance 950 910 820 760 micromhos
Amplification Factor 6.0 5.8 5.6 5.5

Plate Resistance 6300 6400 6800 7200 ohms

Load Resistance 12600 12800 13600 14400 ohms
Maximum Signal Power Output 50 60 150 210 milliwatts

Total Harmonic Distortion 4.0 5.0 6.3 8.0 per cent